study of natural compressed gas cng usng intake valve swirl
TRANSCRIPT
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STUDY OF COMPRESSED NATURAL GAS (CNG) ENGINE USING INTAKE VALVE SWIRL
MOHD SHAHRUL AZMI BIN MOHD AKHIR
A report submitted in partial fulfillment of the requirements
For the award of the degree of
Bachelor of Mechanical Engineering with Automotive Engineering
Faculty of Mechanical Engineering
UNIVERSITI MALAYSIA PAHANG
NOVEMBER 2008
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ACKNOWLEDGEMENTS
I am grateful and would like to express my sincere gratitude to my supervisor
Professor Madya Dr Rosli Bin Abu Bakar for his germinal ideas, invaluable
guidance, continueous encouragement and constant support in making this research
possible. He has always impressed me with his outstanding professional conduct, his
strong conviction for science, and his belief that a Degree program is only a start of a
life-long learning experience. I appreciate his consistent support from the first day I
applied to graduate program to these concluding moments. I am truly grateful for his
progressive vision about my training in science, his tolerance of my nave mistakes,
and his commitment to my future career. I also would like to express very special
thanks to my co-supervisor Mr. Semin Sanuri for their suggestions and co-operation
throughout the study. I also sincerely thanks for the time spent proofreading and
correcting my many mistakes.
My sincere thanks go to all my labmates and members of the staff of the
Mechanical Engineering Department, UMP, who helped me in many ways and made
my stay at UMP pleasant and unforgettable. Many special thanks go to member
engine research group for their excellent co-operation, inspirations and supportsduring this study.
I acknowledge my sincere indebtedness and gratitude to my parents Mohd
Akhir Bin Akasa and Siti Saamah Bt Sukir for their love, dream and sacrifice
throughout my life and understanding that were inevitable to make this work
possible. I cannot find the appropriate words that could properly describe my
appreciation for their devotion, support and faith in my ability to attain my goals.
Special thanks should be given to my committee members. I would like to
acknowledge their comments and suggestions, which was crucial for the successful
completion of this study.
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ABSTRACT
The compressed natural gas (CNG) is the alternative fuel was used in this project for
the modified diesel engine convert to CNG engine. The improvement was giving more
advantage in emission but it was lowering the performance of the engine. This project is
concentrates to improve the air-fuel mixing in the combustion chamber. The modification is
focused on the intake valve part to the new design with added fin. This is to produce the
swirl to the flow of the fuel mixture which entering into the combustion chamber and
produce the turbulent that will increase the combustion ability.
The mix between the fuel and clean air completely could increase efficiency from
the burning for the reduce of emissions. The perfect mix was influenced by the swirl air
flow into intake flow. The addition of fins on intake valve is expected to be able to increase
velocity and the value of the massflow, hence produced more swirl air flow enter into
combution chamber. The configuration of the dimension from fins also could become the
stage factor from swirl.Because of that the analysis of the form is expected to be able to
become a solution to get the form of fins that could give more swirl air flow.This Final
Project is discussed concerning the analysis of the problem above through pemodelan use
the simulation of the computer by software SolidWork. The use of this SolidWork
simulation is very exact because of planning still in the stage conceptual design, so as if
being carried out modelling physical, will need the big cost and relative time for quite a long
time.
Key Words : Intake valve, swirl, fin, SolidWork
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ABSTRAK
Gas Natural Termampat ( GNT) adalah salah satu bahan bakar alternative yang
digunakan di dalam projek ini untuk enjin diesel yang di ubah suai untuk mengubah kepada
enjin GNT. Penambahbaikan memberikan kelebihan dalam pencemaran tetapi ianya
mengurangkan keupayaan enjin. Projek ini menumpukan untuk menambahbaik
percampuran udara dan bahan bakar di dalam kebuk pembakaran. Penambaikan
ditumpukan pada bahagian injap masukan kepada rekabentuk yang baru dengan
penambahan sirip. Ini adalah untuk pembentukkan aliran pusaran campuran bahan bakar
yang masuk ke dalam kebuk pembakaran dan menghasilkan pergolakan yang mana
menambah keupayaan pembakaran.
Percampuran di antara bahan bakar dan udara bersih yang lengkap akan
menambah keupayaan dari pembakaran untuk mengurangkan pencemaran. Percampuran
lengkap telah diberikan oleh aliran udara pusaran ke dalam aliran masuk. Sirip-sirip
tambahan pada injap masukan di jangkakan untuk boleh menambah halaju dan nilai aliran
jisim, dan sekarang lebih aliran udara dihasilkan masuk ke dalam kebuk pembakaran. Rupa
bentuk dimensi dari sirip juga akan menjadi faktor peringkat daripada pusaran. Oleh kerana
itu analisis pembentukan adalah dijangkakan boleh untuk menjadi penyelesaian untuk
mendapatkan pembentukan sirip-sirip yang akan memberikan lebih aliran udara pusaran.
Projek akhir ini adalah dibincangkan mengenai analisis masalah di atas melalui pemodelan
menggunakan simulasi computer oleh perkakas lembut SolidWork. Mengunakan simulasi
SolidWork ini adalah sangat tepat kerana perancangan masih dalam peringkat konsep
rekabentuk, jadi sebagai kalau di ambil keluar fizikal yang dimodelkan, memerlukan dana
besar dan bersangkut paut masa yang cukup panjang.
Kata-kata Kunci : Injap masukan, Pusaran,Sirip , SolidWork
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TABLE OF CONTENTS
Page
SUPERVISORS DECLARATION iiSTUDENTS DECLARATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF FIGURES ix
LIST OF SYMBOLS xi
LIST OF ABBREVIATIONS xii
CHAPTER 1 INTRODUCTION
1.1 Introduction 1
1.3 Problem Statement 2
1.3
1.4
The Objectives of the Research
Project scope
3
3
1.5 Thesis Structure 3
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CHAPTER 2 LITERATURE REVIEW
2.1 Introduction 5
2.2 Internal Combustion Engine 5
2.2.1 Historical perspective 5
2.2.2 Classification of intenal combustion engines 6
2.3 Compressed Natural Gas 8
2.4
2.5
2.6
2.7
Intake valve
Opening Valve
The valve and the Fin
The swirl in the intake port flow
9
12
14
14
CHAPTER 3 DURABILITY ASSESSMENT METHODS
3.1 Introduction 15
3.2 Overview of The Methodology 16
3.3 Project Methodology 16
CHAPTER 4 RESULTS AND DISCUSSION
4.1 Introduction 19
4.2 Model of the cylinder block 20
4.3 Original Valve and Valve with fin 20
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4.4 The original valve simulation result 23
4.5
4.6
The valve with the fin at the side
The graph result for the simulation
26
38
CHAPTER 5 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusions 47
5.2 Recommendations 47
REFERENCES 49
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LIST OF FIGURES
Figure No. Page
2.0 Internal combustion engines 8
2.1 valve place 10
2.2 Valve parts 12
3.0 Flow chart of the final year project 18
4.0 Model of the cylinder 20
4. 1 Original valve 20
4.2 Long bend (LB) intake valve fin 21
4.3 Side bend counter clockwise (SBCCW) intake valve fin 21
4.4 Side bend clockwise (SBCW) intake valve fin 22
4.5 Straight fin (SF) intake valve fin 22
4.6 Original valvevelocity at minimum opening valve lift 23
4.7 Original valvevelocity at middle opening valve lift 24
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4.8 Original valvevelocity at maximum opening valve lift 25
4.9
4.10
4.11
4.12
4.13
4.14
The intake flow velocity for valve type LB 2 fins. The valve opening (a)
minimum, (b) middle, (c) maximum.
The intake flow velocity for valve type LB 3 fins. The valve opening
(a)minimum, (b) middle, (c) maximum.
The intake flow velocity for valve type LB 4 fins. The valve opening (a)
minimum, (b) middle, (c) maximum
The intake flow velocity for valve type SB CW 2 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
The intake flow velocity for valve type SB CW 3 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
The intake flow velocity for valve type SB CW 4 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
26
27
28
29
30
4.15
4.16
The intake flow velocity for valve type SB CCW 2 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
The intake flow velocity for valve type SB CCW 3 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
32
33
4.17 The intake flow velocity for valve type SB CCW 4 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
34
4.18 The intake flow velocity for valve type SF 2 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
35
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4.19
4.20
4.21
4.22
4.23
4.24
4.25
4.26
4.27
4.28
4.29
4.30
The intake flow velocity for valve type SF 3 fins. The valve opening
(a)minimum, (b) middle, (c) maximum
The intake flow velocity for valve type SF 4 fins. The valve opening(a)minimum, (b) middle, (c) maximum
The effect of original valve at different valve lift
The effect of LB valve at with minimum valve lift
The effect of LB valve at middle valve lift
The effect of LB valve at maximum valve lift
The effect of SB CW valve at minimum valve lift
The effect of SB CW valve at middle valve lift
The effect of SB CW valve at maximum valve lift
The effect of SB CCW valve at minimum valve lift
The effect of SB CCW valve at middle valve lift
The effect of SB CCW valve at maximum valve lift
The effect of SF valve at minimum valve lift
36
37
38
39
39
40
40
41
41
42
42
43
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4.31
4.32
4.33
The effect of SF valve at with middle valve lift
The effect of SF valve at maximum valve lift
The effect of valve with 3 fins at middle valve lift
43
44
44
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LIST OF SYMBOLS
Width valve seat
Phi
Density
Valve seat angle
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LIST OF ABBREVIATIONS
CNG
EX
Compressed Natural Gas
Exhaust
IN Intake
LB Long Bend
SB CCW Side Bend Counter Clock Wise
SB CW Side Bend Clock wise
SF Straigth Fin
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CHAPTER 1
INTRODUCTION
1.1 Background
Nowadays, the alternative fuel has been growing due to concerns that the
reserves of fossil fuel all over the world are finite and at the early decades of this
century will run out completely. The vehicle manufacturing researchers have to find
other alternative for replacing the current fuel for the vehicle as the futurepreparation.
Compressed Natural Gas (CNG) is one of the alternative fuel that find that
can be use as the vehicle fuel to replacing the gasoline (petrol) or diesel fuel. This
alternative fuel was having advantages in environment and air pollution control. The
exploitation of full potential of CNG as an alternative fuels is means of reducing
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exhaust emissions. CNG will be coming in the transport sector widely in several
years from now on. In this project the engine used is diesel engine with single
cylinder that will convert to the CNG engine.
This project is about the sequential or trans-intake valve-injection system, a
high speed gas jet is pulsed from the intake port through the open intake valve into
the combustion chamber, where it causes effects of turbulence and charge
stratification particularly at engine part load operations. To increase the turbulent in
the combustion chamber, this project are propose the new design of the intake valve
with improving by adding fin on the side of the valve to make the input mixture swirl
and form the turbulent in the combustion chamber. The valve will be redesign to
increase the intake flow rate and get more complete combustion in combustion
chamber.
1.2 Problem Statement
In CNG engine have low of volumetric efficiency. This problem cause the
low energy density and low of air-fuel intake and low of fuel mixing that will
produce low of power in the combustion chamber. The problem will be base on this
lack ability of the engine that need to improvement. This project is to improve and
increase the volumetric efficiency, air-fuel mixing and turbulent flow into the
combustion chamber.
This project is about to improve the air-fuel intake flow. As velocity increase
and generate more swirl flow to insist the development of the turbulent flow in the
combustion chamber. Therefore the complete combustion will be occurring.
For that, the improvement will be simulating in the related software to
modeling and analyze the data. The suggested software to model and to analyze the
data is SolidWork, Cosmos FloWork. Therefore, a study has to carryout of the result
that can come out the problem.
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1.3 Problem Aim and Objective
To develop the computational model of intake valve swirl for sequential injection
CNG engine flow.
1.4 Project Scope
In order to archive the research objective stated above, the following scopes
of work have been defined:
1. Identify the literature review of the project.2. Intake valve designed using fin for swirl flow.3.The computational design is using SolidWork and Cosmos FloWork
software.
4. Intake valve swirl will be developed in several types.5. Analysis the effect of intake valve fin in CNG engine performance using
simulation.
1.5 Thesis Structure
Thesis structure is briefly explanation to every chapter in this thesis. The
structure of the thesis is as below:
1. Chapter 1This chapter discuss briefly on the project background, problem statement,
project objective, and project scope. The main purpose of this chapter is to
give early understanding of the overall project.
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2. Chapter 2This chapter includes all the information acquired regarding on the project
which includes the quotes and summary from the journals, reference books
and other types of article review. All of the information including the
principles, explanations and parameters related to this project were shown in
this chapter for future reference.
3. Chapter 3All the methodologies are discuss clearly in this chapter and was illustrated in
flow chart for better understanding.
4.
Chapter 4All the data collected will be further to result analysis. The data was
interpreted and will be analyze detail. The simulation test result will be
discussed and analyzed.
5. Chapter 5This chapter is the conclusion for the whole project and determines whether
this project had achieved its objectives as stated in chapter 1. Further work
such as design improvement also has been discussed in this chapter for futureproject development.
1.6 Summary
This project is proposed for the new design of the intake valve in the intake
port flow of the internal combustion compartment part. The design was simulate by
SolidWork and Cosmos FloWork software that suggested from the supervisor of this
project. The analysis is narrow to increase the flow rate in the intake port flow of the
mixture to the combustion chamber to increase the swirl and produce more turbulent
for the better complete combustion of the fuel mixture.
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CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
This chapter explain about the basic principle in the internal combustion
engine, four- stroke operation, the intake valves operation, part with new
improvement and importance process in the combustion engine which taken from the
journals, reference books, and other related resources.
2.2 Internal Combustion Engine
2.2.1 Historical Perspective
The history of internal combustion engine is started byAb al-'Iz Ibn Ism'l
ibn al-Razz al-Jazar from 1136-1206. He described a double-acting reciprocating
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piston pump with a crank-connecting rod mechanism. After that at 17th century the
english inventor Sir Samuel Morland used gunpowder to drive water pumps,
essentially creating the first rudimentary internal combustion piston engine. At 1806
the Swiss engineer Franois Isaac de Rivaz built an internal combustion engine
powered by a hydrogen and oxygen mixture. In 1860 Belgian Jean Joseph Etienne
Lenoir (18221900) produced a gas-fired internal combustion engine similar in
appearance to a horizontal double-acting steam beam engine, with cylinders, pistons,
connecting rods, and flywheel in which the gas essentially took the place of the
steam. This was the first internal combustion engine to be produced in numbers.
Then until now so many improvement and modern engine type was built by the
investor. When comparing the modern versus historical pistons engines, the first
piston engines did not have compression, but ran on an air-fuel mixture sucked orblown in during the first part of the intake stroke. The most significant distinction
between modern internal combustion engines and the early designs is the use of
compression and, in particular, in-cylinder compression.[2][10]
2.2.2 Classification of internal combustion engines
Internal Combustion Engine is refer to the small amount of high energy fuel
enter in the combustion chamber have ignited and incredible amount of energy
release.[2] All internal combustion engines depend on the exothermic chemical
process of combustion: the reaction of a fuel, typically with the oxygen from the air,
although other oxidizers such as nitrous oxide may be employed. Also see
stoichiometry. The most common m3odern fuels are made up of hydrocarbons and
are derived mostly from petroleum[2][10] These include the fuels known as diesel
fuel, gasoline and petroleum gas, and the rarer use of propane gas. Most internal
combustion engines designed for gasoline can run on natural gas or liquefied
petroleum gases without major modifications except for the fuel delivery
components. Liquid and gaseous biofuels, such as ethanol and biodiesel (a form of
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diesel fuel that is produced from crops that yield triglycerides such as soybean oil)
can also be used. Some can also run on hydrogen gas.[2][4][5][10]
The purpose of internal combustion engine is the production of mechanical
power from the chemical energy contained in the fuel. In internal combustion
engines, as distinct from external combustion engines, this energy is released by
burning or oxidizing the fuel inside the engine. The fuel-air mixture before
combustion and the burned products after combustion are the actual working fluids.
The work transfers which provide the desired power output occur directly between
these working fluids and the mechanical components of the engine. The internal
combustion engine is subjected of spark-ignition engines (sometimes called Otto
engines, or gasoline or petrol engines, though other fuels can be used) and
compression-ignition or diesel engines. Because of their simplicity, ruggedness and
high power/weight ratio, these two types of engine have found wide application in
transportation (land, sea and air) and power generation. It is fact that combustion
takes place inside the work producing part of these engines that make their design
and operating characteristics fundamentally engines different from those of other
types of engines.[2][6][10]
In this internal combustion engine analysis the project is using the
compressed natural gas engine as the alternative fuel. This project is use diesel
engine that converts to Compressed Natural Gas engine. The modification is only in
replacing fuel from diesel fuel to CNG fuel and also using spark plug to ignite the
air-fuel mixing in the combustion chamber.
The term Internal Combustion Engine is almost always used to refer
specifically to reciprocating piston engines, Wankel engines and similar designs in
which combustion is intermittent. However, continuous combustion engines, such as
jet engines, most rockets and many gas turbines are also internal combustion engines.
[1] This engine is use four stroke engine. The four stroke engine refer to intake,
compression, combustion and exhaust strokes that occur during two crankshaft
rotations per working cycle of Otto Cycle and Diesel engines. [3][4] The four steps
in this cycle are often informally referred as suck, squeeze (or squash), bang,
blow.The four strokes of the internal combustion engine are as follows (and in
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order): Intake, Compression, Power, and Exhaust. These four strokes require two
revolutions of the crankshaft. The process continuously repeats itself during the
operation of the engine.[3][9]
Figure 2.0: Internal combustion engines
2.3 Compressed Natural Gas
Compressed Natural Gas is one of the alternative fuel that found that can be
use as the vehicle fuel to replacing the gasoline (petrol), diesel, or propane fuel. This
alternative fuel was having advantages in environment and air pollution control. It is
considered to be an environmentally "clean" alternative to those fuels and it is much
safer than other motor fuels in the event of a fuel spill. In that case natural gas is
lighter than air, so it disperses quickly when leaked or spilled. The exploitation of
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full potential of Compressed Natural Gas as an alternative fuels is means of reducing
exhaust emissions. It is made by compressing natural gas (which is mainly composed
of methane (CH4)), by about 75%. It is stored and distributed in hard containers, at a
normal pressure of 200220 bar (2022 MPa), usually in cylindrical or spherical
shapes to maintain equal pressure on the walls of the containers. Compressed Natural
Gas will be coming in the transport sector widely in several years from now on. In
this project the diesel engine with single cylinder will converted to the Compressed
Natural Gas engine[1][3][4][8][13].
2.4 Intake Valve
Valve is the part of the component that has the mechanism to open and close
the entry of air, which in this case is in combustion chamber. Every cylinder has two
valve, intake valve and exhaust valve respectively. The mechanism of the valve is:
Valve
a. Material :Its made from the hard metal with other element, like coal substance,
silicone, chrome nickel, wolfram. For intake valve is made by combining the
chrome nickel and exhaust valve made by silicone compound.
b. Used :1. To open and close the gas/air entry and to throw out the exceeded burned
gases in the relative time.
2. Avoid the compression leaking and combustion explosion.
c. Valve requirement :1. Light weight and have valve seat with 45 or 30 on the side.2. High strength and high vibration to hold out.
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3. Long life time in using and the valve seat is closed to the cylinder headseat.
Figure 2.1: Valve place
d. Type of valve
Intake valve:
The valve used as the door of the air/gases enters for supply the
machine from the intake port. The valve plate is built in fine plate in order
that lightening the swirl load on pivot roof.
Exhaust valve:
The valve used as the door to throw out the exceeded gases from the
internal combustion chamber to the exhaust port. The valve plate is build in
thick at intake valve in order that can endure heat and not easy to change the
shape.
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The Difference of intake valve and the exhaust valve:
Intake Valve:
1. Usually valve diameter is bigger than exhaust valve.
2. Have IN marked.
3. Have attraction to the magnet.
Exhaust Valve:
1. Usually the valve diameter is smaller than intake valve.2. Have EX marked.3. Not attract to the magnet because of the large amount of nickel
compound.
Mechanism of valve parts:
Figure 2.2: Valve parts